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Re: Small MicroVAX IIs - what version? - was Re: NetBSD/vax current



On 2014-04-13 23:12, Toby Thain wrote:
On 13/04/14 4:35 PM, John Klos wrote:
I'm going to try and do some more testing, but I really can't see many
other explanations. I noticed that just booting NetBSD up on the
4000/90 grabbed more than 16M before the boot was complete, so with
only 16M it is going to be paging a lot.

NetBSD 6 runs OK on a VAXstation 4000/30 with 24 megs. Not great, but OK.


Any recommendations for a MicroVAX II with 9MB? I have 1.4.1 netbooting
on it right now and it's pretty happy - was able to compile Apache
1.3.x, etc.

Is 1.5 okay for such a small system? I've read conflicting opinions.

If you ask me, 1.6 is just fine as well. 2.0 is still also pretty ok. I'm not sure exactly when things became horrible, but back in those versions, NetBSD was still pretty snappy, as far as I can remember. (Used to run a VAX-11/750 with it, and still thought it was acceptable.)

On another side note, NetBSD/vax (but I sortof notice something similar on other architectures) are hitting the namei sys-cache a lot. And when that happens, the system is spending the majority of the time in system, and are not making much progress on anything. There seems to be a very clear correspondence between the namei calls and the amount of time spent in system. With gcc just chugging along trying to compile a file, I see maybe 1000 namei calls in 5s (looking at system). With this, I have about 10% system time. When namei calls jumps to above 6000 I have more than 50% time in system, sometimes going up to over 80%. The correlation is not absolute, but there definitely seems to be some connection between them.

I recently fired up an Alpha with current, and sometimes the namei calls jumps up to over 100.000, which I found rather impressive. (Although maybe also depressing.) And of course, that machine also spent large chunks of time in system.

http://vax.zia.io/

The hardware isn't as cool as an 11/785, but it's a bit more affordable
to run :)


   Well, get to it, man! ;)  I expect there will eventually be a
fork of
NetBSD that will trim the fat and make it more usable.  Testing on
older, slower hardware would go a long way toward "keeping it honest".

Question is if anyone have the time, energy and money for that to
happen?

It'd be nice to see pcc for VAX instead of gcc. gcc has way too much fat
and take way too long to do anything. And I wonder how much better an
entirely crunchgen'd NetBSD would be on a very low memory machine...

I wonder if lcc does a better job than pcc. lcc is ANSI and has a VAX
code generator, that's fairly easy to modify.

https://sites.google.com/site/lccretargetablecompiler/

I think that Ragge have gotten pcc more or less to compile most of NetBSD, so ANSI is not a problem.

        Johnny

--
Johnny Billquist                  || "I'm on a bus
                                  ||  on a psychedelic trip
email: bqt%softjar.se@localhost             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol


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